The NSA has discovered a critical vulnerability (CVE-2020-0601) affecting Microsoft Windows cryptographic functionality. The certificate validation vulnerability allows an attacker to undermine how Windows verifies cryptographic trust and can enable remote code execution.
The vulnerability affects Windows 10 and Windows Server 2016/2019 as well as applications that rely on Windows for trust functionality. Exploitation of the vulnerability allows attackers to defeat trusted network connections and deliver executable code while appearing as legitimately trusted entities.
Examples where validation of trust may be impacted include:
- HTTPS connections
- Signed files and emails
- Signed executable code launched as user-mode processes
The vulnerability places Windows endpoints at risk to a broad range of exploitation vectors. NSA assesses the vulnerability to be severe and that sophisticated cyber actors will understand the underlying flaw very quickly and, if exploited, would render the previously mentioned platforms as fundamentally vulnerable.
The consequences of not patching the vulnerability are severe and widespread. Remote exploitation tools will likely be made quickly and widely available. Rapid adoption of the patch is the only known mitigation at this time and should be the primary focus for all network owners.
We recommend installing all January 2020 Patch Tuesday patches as soon as possible to effectively mitigate the vulnerability on all Windows 10 and Windows Server 2016/2019 systems.